Potency of a recombinant NDV-H5 vaccine against various HPAI H5N1 virus challenges in SPF chickens.

For the past decade, several recombinant Newcastle disease viruses (rNDV) have been used as a vector to express native or modified avian influenza (AI) hemagglutinins (HA) in order to give preventive protection against highly pathogenic avian influenza (HPAI) H5N1 viruses. Obtained protections were dependent on the age of the chickens, on the constructs and, in particular, on the homology between the HA that was inserted and the challenge strains. The objective of this study was to investigate the vaccine efficacy of a recombinant NDV La Sota-vectored vaccine expressing an Asian clade 1 H5 ectodomain (rNDV-H5) vaccine expressing a modified H5 ectodomain from an HPAI clade 1 H5N1 isolate as vaccine for 1-day-old specific-pathogen-free chickens.

A chemically defined production process for highly attenuated poxviruses.

Highly attenuated poxviruses are promising vectors for protective and therapeutic vaccines. These vectors do not replicate in human cells and can therefore be safely given even to immunocompromised recipients. They can accommodate very large inserts and provide strong stimulation of the immune system against the vectored antigen.

A field study on the significance of vaccination against infectious bursal disease virus (IBDV) at the optimal time point in broiler flocks with maternally derived IBDV antibodies.

The right strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level and variation in maternally derived IBD antibodies, and the IBD vaccine strains to be used. Usually, standard vaccination programmes are used, which are not always adapted to the specific conditions on the farm and to the immune status of chickens. Employing the "Deventer formula" may help to estimate the optimal time for vaccination for a specific flock based on the maternally derived antibody level, its variation, the genetic background of the chicken, and the IBD vaccine strain.

Characterization of duck leucocytes by monoclonal antibodies.

cDNAs encoding CD3epsilon, CD4 and the alpha-chain of CD8 of ducks were cloned. Monoclonal antibodies against Pekin duck CD4 and CD8alpha revealed that the antigens were expressed by the majority of thymocytes and by subpopulations of CD3+ cells in peripheral tissues. CD8alpha cell surface expression was also found on 90% of bursal cells.

Performance of enzyme-linked immunosorbent assays for detection of antibodies against T. congolense and T. vivax in goats.

Indirect ELISAs using denatured antigen preparations of Trypanosoma (T.) congolense (TcAGd) and T. vivax (TvAGd) for detection of anti-trypanosome antibodies in bovine serum (I-TAB ELISAs), were adapted for serodiagnosis in goats.